Increasing body mass index at diagnosis of diabetes in young adult people during 1983-1999 in the Diabetes Incidence Study in Sweden (DISS).

OBJECTIVE To study trends in body mass index (BMI) at diagnosis of diabetes in all young Swedish adults in the age range of 15-34 years registered in a nation-based registry. DESIGN The BMI was assessed at diagnosis in diabetic patients 15-34 years of age at diagnosis, for a period of 17 years (1983-1999). Islet cell antibodies (ICA) were measured during three periods (1987-1988, 1992-1993 and 1998-1999). SETTING A nationwide study (Diabetes Incidence Study in Sweden). SUBJECTS A total of 4727 type 1 and 1083 type 2 diabetic patients. MAIN OUTCOME MEASURES Incidence-year specific BMI adjusted for age, gender and time of diagnosis (month). RESULTS Body mass index at diagnosis increased significantly both in type 1 (21.4 +/- 3.6 to 22.5 +/- 4.0; P < 0.0001) and in type 2 (27.4 +/- 6.8 to 32.0 +/- 6.0; P < 0.0001) diabetic patients, also when adjusted for age, gender and month of diagnosis. A similar significant increase in BMI was found in type 1 diabetic patients and in type 2 diabetic patients in the periods 1987-1988, 1992-1993 and 1998-1999; years when ICA were assessed and considered in the classification of diabetes. Despite this increase in BMI, there was no increase in the incidence of diabetes in young-adult people in Sweden. CONCLUSION Body mass index at diagnosis of diabetes in subjects 15-34 years of age has substantially increased during 1983-1999 in Sweden when adjusted for age, gender and month of diagnosis.